Electrical signaling



' May 19, 1925.

1,538,466 L. COHEN ET AL ELECTRICAL SIGNALING Filed Oct. 25, 1920 4 Shets-Sheet 1 Deiecior Lou/Ls Cohen "w J. 0. Maubolgne May 19, 1925.

L. COHEN ,ET AL ELECTRICAL SIGNALING Fi'led 00's. 25, 1920 4 Sheets-Sheet 12 l l 13 141mm toz Lou/ls Cohen w J 0.17aub0/g/1e .Diecfov May 19, 1925. 1,538,466

L. CQHEN ET AL v ELECTRICAL SIGNALING Filed oct. '25, 1920 4 Sheets-Sheet 5 May 19, 1925. 1,538,466

COHEN ET AL ELECTRICAL SIGNALING Fild Oct. 25, 1920 r 4 Sheets-Sheet 4 F'.Z -1 (L7 avwewroz Lou/Is Cohen w J. 0. [Yquborgne Patentedll/Iay 19, 1925?- p I UNITED STATES LOUIS oo'nmr AND JOSEPH o.

'PA-TENT OFFICE,

munonenn, on wasmneron, nrsrnrc'r or cononnm. 1

' nnncrarcm. SIGNALING.

I Application filed October 25, 1920. -S'e'ria1 No. 419,383.

si ale and thus improve the clearness and; re iability of radio communication. I In a pending application, Serial Number l:() 1,'t'52,- .we have 'describeda method for receiving radio signals. in which resonance wave coils are introduced in an antenna circult, and utilizing the wave development efiects produced by electrical excitation acting on theantennal The present invention is another modificati not the same general idea'embodyin novel features with a view to securing stil' greater improvements in the results desired, namely, more'eflective elimination of Staticdisturb'ances and other inter-/ ference in the receptlon of radio signals.

The method involves the use of anopen antenna circuit, no ground, and the use of resonance wave coils as part of the antenna circuit, thereby effecting a wave development in the antenna system and suitably connecting an indicator either direct/or to aisecondary coupled circuit to a loop of potential point on the wave coil. The res-,

onance wave coil which we shall designate hereinafter simply aswave coil,,is1.pret.

erably in the form of a long helix, uniformly ..:wound with -W11'6, single or multiple layer winding, the electrical constants of which,"

inductance, caplacity, and i'esistance, are of a distributed c aracter and agwave' dei'elopmerit-effected on the wave coil by a, elec-. trical excitation of the antenna. The wave coil is wound" with a large number bf turns per unit length, and alsoenclos'eddor part of its length, or the entire length,,'by one or more adjustable grounded metaltubes suitably placed on the wave coil, the object being to secure a large inductance and a large capacity per unit [length so fas to get in a comparatively Short length 'the equivalent condition of a longline in the matter of wavedevelopmenti Also by the ad'ustment of the position of the metal tubes tuning is.

efl'ected which produces an increase in the intensity of the signal to be received and a redirection of foreign. disturbances such as electrostatic efi'ects. Qne or all of the metal .tubes surrounding the wave coil ma be di- 'rectly connected to ground or throug a loop circuit consistin pacit in paralle the constants of which are suita 1y. adjusted in relation to the frequency of the signals it is desired to receive.

The principle involved is to permit all ielectrical efiects 'actingon the antenna to pass through the wave coils before reaching 1 the receiving instrument. It is welLkno'wn that an electrical shock effect such as inav be produced by electrostatic disturbances, strays, or nearby radio stations, has a/much steeper wave front than the oscillations produced b incoming, signals which are regular in ciaracter inthe matter of intensity and frequency. The electrical shock effects of steep wave fronts are more apidly attenuated in passing through a conductor in of an inductance and 021- 'wh'ch a wave development is efiec'ted -by these electrical disturbances, and as a result a/much hlgher ratio of signal to static is obtained in the receiving instrument. By suitably adjusting the constants of the wave coil in the matter of length, number of turns, etc'., and also properly adjusting the position of the metal. tubes surrounding the coils, all in relation to the wave length of the signals /to be received, a condition is obtained where electrostatic or other foreign disturbances are largely attentuated, leaving the receivingiinstrument free from these disturbances and acted .on onlyby the signals it is desired to.receive. Further use of the loop circuit in the ground connection of the metal tubes is of considerable importance in bringing about the results desired. It the loop circuit is tuned to the frequency of the signal it is desired to receive, it ofiers an extremely high impedance to the signal received, preventing any of the signal energy from leaking away by that path to the ground, but ofiering a ready path for any other electric disturbances. which are not exactly of the same frequency. It is evident also that the loop circuit with its ground connection, functions in a different way when the system is actedlupon by foreign disturbances than of foreign disturbances which are of a different frequency.-

In other words, 1n the arrangement disclosed in this invention any electrical effect acting on the antenna is propagated along the Wave coil in the form of an attenuated wave, the attenuation and wave length depending upon the character of the electrical disturbances acting on the antenna in relation to the circuit arrangement. By properly adjusting the length of wire on the wave coil, the position and dimension of the metal tubes, and constants of the loop circuit all in relation to the frequency of the signal to be received, a condition may be realized Where the attenuation of the signal current is very feeble, while other interfering effects of different frequencies are attenuated very sharply in their propagation along the wave coil.

It should also be borne in mind that for the propagation of electrical waves in the free ether, there is one definite fixed relation between the frequency and the wave length, but in the case of propagation of electrical waves along coils, the relation between frequency and wave length is dependent upon the electrical characteristics of the coil, its inductance and its capacity, which also offers a means for controlling the wave length. The adjustment of the metal tube and the grounded loop circuit have an equivalent effect as changing the electrical characteristics of the coil, and-hence, cause a change in the wave length of any electrical effect propagated along the wave coil. The arrangement involving this invention offers, therefore, a means of controlling both the wave length and the attenuation constants of the wave propagated along the wave coil, and by suitable adjustments, these properties can be advantageously employed to ac centuate the signal to be received and practically nullify all foreign disturbances in their effects upon the detecting instrument. By placing several metal tubes on the wave coil, each grounded through different loop circuits, there is, obtained the equivalent effect of several separate wave coils of different electrical constants joined together electrically due to the direct connections and electro-magnetic relation between the different parts of the wave coil, and in this instance, any single frequency current may produce a multiplicity of waves of different wave lengths, and with proper adjustments of the phase relations of the different waves produced by the signal to be received, an additive effect upon the detector is obtained. Obviously, this offers an additional means of differentiating the signal effect fromany foreign disturbances.

The circuit combination described above offers a very effective-method for increasing greatly the ratio of signal to static, thereby improving the clearness and accuracy in radio communication.

The principle of operation and the method of using our invention can be better understood by reference to the accompanying diagrammatic'ligures which show typical embodiments of the invention and form part of this specification.

In the accompanying drawings:

Figure 1, is a diagrammatic view of a system for carrying out the invention in which the receiving circuit is coupledclectro-statically to a wave coil.

In Figure 2, the receiving circuit, including the detector, is connected directly to a suitable point on a Wai e coil.

Another embodiment of our invention is shown in Figure 3 in which an additional wave coil is connected electr c-statically to a' suitable point on a wave coil of the antenna system, and the receiving circuit proper, including the detector is coupled electro-magnetically to the additional wave coil.

The arrangement shown in Figure at differs from that of Figure 3 in that the electro-static connection of the wave coil of the antenna system passes through a small vari able condenser before being connected to an additional wave coil, and one point of said condenser is grounded through a suitably adjusted loop circuit.

In Figure 5, an arrangement is shown in which the receiving circuit, including the detector, is coupled elect-ro-magnetically to a wave coil of the antenna system.

Figure 6 is an embodiment of our invention in which the end part of the wave coil of the antenna system is closed upon itself through a suitable inductance and capacity,

and the receiving circuit, including the dc tector, is coupled electro-magnetically to the wave coil of the antenna system, and also to the inductance of the connecting circuit, and

Figure 7 is a digrammatical view of a possible modification of our invention.

Having particular reference to the draw ings, and in connection with which, like characters of reference will designate corresponding parts thereof, in Figure 1, the antenna l is connected to a variable inductance 2, in series with variable capacity 3, and in tubes 6 and 6 are connected to a loop circuit The metal tubes 6 and 6 which are electrically connected by a lead 7, are movableand can slide along the coil f1. Also the. metal consisting of a variable inductance 8 and a variable capacity 9, connected in parallel, and then to ground 10. 11 indicates a metal ring movable along coil 5, the metal ring being connected electrically to one point of a circuit consisting of a variable inductance 12 and a variable capacity 13. 14 represents an indicating instrument connected 'across the condenser terminals 13,

The operation is as follows:

In Figure 1, the tuning of the antenna system is accomplished b varying Iinductance2, capacity 3, and t e adjustment of the metal-tubes-6 and 6' along the coil 4. Experiencehas shown that by suitably adjusting the position of the metal tubes 6 and 6 relative to each other and varying their positions on the coil very. sharp tuning is. obtained. Further .by adjustment of the metal tubes 6 and 6 it is possible either to bring in thesignal andeliminate foreign disturbancesor vice versa. Hence the ad justment of the metal tubes plays a very im-' portant part in changing the ratio of static to signal acting on the receiving instrument.

' In fact, it may be said that this arrangement. offers for the first time a means for varylng.

the ratio of static to signal. The tuning of the loop circuit 8-9. is also very effective in increasing the loudness of the signal it is desired to receive without [at the same time bringing in static disturbances. In fact, with proper adjustment of the loop circuit 8 9, the signals are. intensified, while theelectrostatic or other foreign disturbances are reduced. Thering 11 is adjustable along 'coil 5, and .in actual operation it ismoved-along the coil until the loudest signal is obtained. The ring constitutes an electrostatic coupling betweenthe coil 5, and the' receiving circuit 12-.13. Evidently the ring 11 must be adjusted so as to be on .a loop of potential point of coil 5. Circuit is tuned to the frequency of the inc oming sig.

nal. 14 indicates a suitable-detector which may be anyone of the well-known types, suchas the three electrode tube, or any other detector connected across the terminals of the secondary condenser 13.

Figure 2 difl'ers only from Figure in the .method of connecting the receiving circuit 12-13 to the wave coil 5. 1 In this arrange nient a direct connection is used. The circuit 12-13 connects to variable point 17 along the coil 5, said, connectionbeing moved along the coil 5 until the point of maximum sensitiveness is obtained, which,

in this case, would be the 'loop of potential point on the coil 5.

Another embodiment of the invention is shown in Figure 3 in which an additional I wave coil 15 is used. The wave coil 15 is connected lelectrostatically through metal ring 11 to the wave coil 5, and the secondary circuit 12 13" is coupled electro-magnetically to the wave coil '15. The object of using additional wavecoil 15 is to produce aneincrease in the selectivity of the system, thereby still further reducing any foreign disturbances which might otherwise find their way into the receiving system.

Figure 4'dilfers from Figure 3 by the introduetion of an additional variable con- .denser 18 into the connecting lead which connects coil 15 to the metal ring 11 which is in its turn electrostatically coupled to coil 5. In addition, loop circuit 19-20, grounded to 10, is also connected to one point of condenser 18. The purpose of this loop circuit 19 20 is to further drain off all residual foreign disturbances which 'might have" found their way intocoil 15; in other words, the use of coil 15, loop circuit ,1920,- and condenser 18 is simply an additional means of improving the selectivity of the system and further reducing foreign disturbances from acting on the receiving circuit proper 1213 associated with its detector 14.

- In Figure 5, is shown an embodiment of the invention in which the electro-static.

coupling represented by the metal ring 11, referred to in the previous diagrams is here replaced by an-electromagnetic coupling 16.. Also it may be noted that in this arrangement, a variable condenser 27 is shown in the-lead which connects the metal tubes 6 and 6 'to the loop circuit 89. This is sometimes helpful in making the loop circuit more effective in its action'and in the reduction of static disturbances.

The embodiment shown in Figure 6 "fthe terminal arrangement used, but/embodying the same general principles, In this arferssomewhat from the previous fig re in rangement coil5 is divided into two parts,

the end part of which is closed upon itself through a, tuned circuit, consisting of i nductance 22 and capacity 23. The receiving circuit 12.13is coupled to the wave coil- \5 and also to the-tuned circuit 22-22% It is obvious that various modifications ;of the circuit arrangements. may be made without departing from the spirit of the invention. For the purpose of illustration t 0 metal tubes connected electrically-are shown throughout in all the figures, but equally. good results. are "obtained by using either a single tube or several tubes, and the tubes 6, 6, 6", and 6 may or may not all be connected electrically. Further, as shown in Figure 7,-- we may connect either loop circuit or independent loop circuits, including inductances 8 and 8 and variable capacities 9 and 9, or only a portion of the tubes may be connected to ground, and the rest remain free. Either of these variations if proper adjustments are made, will give the .results desired. Also in the case of Wave coils employed only two wave coils are shown in the drawing, but under certain conditions it may be preferable to use only one or a larger number of wave coils. It is clearly within the province of the invention to introduce'these variations.

We claim:

1. A system for radio signaling in which the received signals or other electrical effects acting on an ungrounded antenna system are caused to pass through a wave coil and produce a ave development on said wave coil, said wave coil being operatively associated with adjustable. metal tubes and a suitable indicating instrument.

2. A system for radio signaling in which the received signals or other electrical effects acting on an ungrounded antenna system are caused to pass through wave coils, and produce wave developments on said wave coils, and said wave coils being operatively associated with adjustable grounded metal tubes and a suitable indicating instrument.

3. A system for radio signaling in which the received signals or other electrical .e'tfects acting on an ungrounded antenna system are caused to pass through wave coils before reaching the receiving in- I strument, one of said wave coils being oni the said wave coils.

closed in two adjustable grounded metal tubes separated from each other, said metal tubes being connected to ground through a tuned loop circuit and suitable indicating instrument being operativelv associated with another of said wave coils.

4. A system for radio signalingin which the received signals or other electrical effects acting on an ungrounded antenna system are caused to pass through wave coils before reaching the receiving instrun'ient, one of said wave coils being enclosed in several adjustable grounded met-a1 tubes separated from each other. said metal tubes being connected to-ground through a tuned loop circuit, and suitable indicating instrument being operatively associated with another of 5. A system for radio signaling in which the received signals or other electrical etlect's acting on an ungrounded antenna system are caused to pass through wave coils before reaching the receiving instrument. one of said wave coils being enclosed in adjustable metal tubes, certain of said metal tubes beingseparately connected to ground through a tuned loop circuit, and a suitable indicating instrument being operatively associated with one of said wave coils.

6. A system for radio signaling in which the received signals or other electrical effects acting on an ungrounded antenna system are caused to pass through wave coils before reaching the receiving instrument, one of said wave coils being enclosed in adjustable metal tubes, only one of said metal tubes being connected to ground through a-tuned loop circuit, and a suitable indicating instrument being 'operatively associated with one of said wave coils.

7. A system for radio signaling in which the received signals or other electrical effects acting on an ungrounded antenna system are caused to pass through a Wave coil before reaching the receiving instrun'ient, said wave coil being enclosed in two adjustable grounded metal tubes electrically con nected, said metal tubes being connected to ground through atuned loop circuit and suitable indicating instrument being operatively associated with the said wave coil.

8. A system for radio signaling in which the received signals or other electrical efiects acting on an ungrounded antenna system are caused to pass through two wave coils connected electrically but separated from each other, one of said wave coils being enclosed in two adjustable metal tubes which are. grounded through a tuned loop circuit and the other of said Wave coils being operatively associated with receiving means.

9. A system for radio signaling in which the received signals or other electrical effects acting on anu'ngrounded antenna system are caused to pass through two wave coils connected electricall" but separated from each other, one of said wave coils being enclosed in adjustable grounded metal tubes, the'other of said wave coils being eleetrostatically associated with a third wave coil, and receiving instruments being electrically associated with the said third Wave coil.

10. A system for radio signaling in which the received signals or other electrical efl'ects acting on an ungrounded antenna system are caused to pass through two wave coils connected electrically, one-.of said wave coils being enclosed in adjustable metal tubes, said metal tubes being connected to ground through tuned loop circuits; the other of said wave coils being electro-statically asto a tuned circuit and a detecting instrument associated with said tuned circuit.

12. A system for radio signaling comprising an antenna, tuning elements, two wave 0011s, one of said wave coils being enclosed in adjustable metal tubes, said metal tubes being connected to ground through a tuned loop circuit, another tuned circuit being connected to an adjustable point on the other of said wave coils, and a suitable indicating instrument being associated with said tuned circuit. 1

13. A system for radio signaling comprising an antenna system, which consists of an antenna, tuning elements, two wave coils, all connected in series, one of said wave coils being enclosed in adjustable metal tubes, said metal tubes being electrically connected and also connected to the ground through a tuned -loop circuit; the other of said wave coils being electro-statically connected by means of a sliding metal ring on it to a third wave coil, a tuned circuit being electro-magnetically associated with the said third wave coil and a detecting instrument associated with said tuned circuit.

14. A system ;for radio. signaling comprising an antenna system which consists of an antenna, tuning elements, two wave coils, one of said wave coils being enclosed in adjustable metal tubes, said metal tubes being electrically connected and grounded through tuned loop circuits; 'the other of said wave coils being associated electrically with a third wave coil by means of a metal ring sliding over the second said wave coil, said metal ring being connected through a variable condenser to the third of said wave coils, and said variable condenser being grounded through a tuned loop circuit, an-,

other tuned circuit being associated electromagnetically with the third of said wave coils and an indicating instrument connected to said tuned circuit.

LOUIS COHEN.

J. O. MAUBORGNE. 

